11 January 2011

cargo zipline

I recently completed a project with my 7th graders entitled, you guessed it, "Cargo Zipline." I got it from my favorite source of technology/engineering projects: pbskids (scroll down, it's called "On Target"). I adapted it to the manufacturing unit, saying that a big part of manufacturing is automation. I told the students that if you can get machines to do the work for you, everyone saves and everyone ends up with more money. Unfortunately, with automation, you must design a machine that not only works, but works consistently. Factories lose money any time their machine produces a faulty product just because something didn't transfer well from one part of the production to another.

That's where their project comes in. Students work in groups of 3-5 to create a device to carry a golf ball (for some reason I simply cannot find marbles to buy, and I have a bunch of golf balls from another project) from the top of the zipline to the bottom, at which points it drops the ball into a chute below. I ended up creating two ziplines using cheap fishing line. The zipline construction doesn't matter too much, but a good target is 6ft long, with a vertical drop of 2ft. I hooked up 2 ziplines to allow more people to test their device at the same time. Here's a specific list of materials to be given to each group:

1 medium paper cup

1 large paperclip

1 3x5 card

masking tape (I didn't limit the amount, but I got on their case if they were taking too much)

High tech: I stuck a push pin into my speaker shelf and tied the fishing line to it.

I needed to attach my zipline to something tall, and I had this fan in my classroom. The requirement was for the ball to end up in the cup at the bottom of the chute.

Some student examples.

For grading, I gave them three chances to send it down. They got points for each successful launch/drop, points for how easy it was to hook up, and a chunk of participation points just for trying.

I had never done this project before, so the guinea pig class got no help from me. When I saw several groups making the same mistakes, I ended up telling the following classes to be aware of those problems. That's basically the formula for every project I do in this class: assign it to the first class, see what problems they face, discover all sorts of logistics problems with materials and working space and such, and get better over the next three periods.

Anyway, in the end, I was pretty pleased with the variety of designs the students came up with. It was a lot of fun. If any students finished way ahead of time, I gave them a single paperclip and see if they can bend it to carry a golf ball down and drop it at the end.